<p>For ages, money has meant little metal disks and rectangular slips of paper. Yet the usefulness of physical money&mdash;to say nothing of its value&mdash;is coming under fire as never before. Intrigued by the distinct possibility that cash will soon disappear, author and&nbsp;<em>Wired</em>&nbsp;contributing editor David Wolman sets out to investigate&nbsp;the future of money&hellip;and how it will affect your wallet.</p>